In metal cutting operations which require a smooth surface finish and in which milling cutters having multiple cutting inserts are used, the cutting inserts have to be positioned with the greatest possible accuracy, particularly in the axial direction. Non-accurate axial positioning of the cutting inserts results in axial runout which gives rise to poor surface finish and reduction in lifetime of the cutting inserts.
In milling cutters in which each cutting insert is secured to a replaceable cartridge clamped to the cutter body, the axial position of the cutting inserts can be adjusted by adjusting the position of the cartridges in the axial direction until all the operative cutting edges of the cutting inserts lie in a common plane. The simplest way of adjusting the position of such a cartridge is by unclamping the cartridge from the cutter body, manually re-positioning the cartridge to the desired position and then reclamping the cartridge to the cutter body. This process is both time consuming and not always accurate due to movement of the cartridge during re-clamping.
U.S. Pat. No. 5,102,268 discloses a milling cutter having a plurality of cutting insert retaining cartridges circumferentially spaced about the outer periphery of the cutter body. An adjustment mechanism for each cartridge includes an adjustment screw threaded into a corresponding inclined throughbore in the cutter body. The axis of the adjustment screw and the throughbore is coincident with a radius extending from the center of the cutter body. The head of the adjustment screw projects into the inclined throughbore so that when the adjustment screw is turned, the head of the screw bears against the inner surface of the throughbore causing the cartridge to be axially displaced. A locking screw is tightened to secure the cartridge in place after it has been adjusted. In order to accommodate the head of the adjustment screw in the throughbore, the throughbore has to be dimensioned larger than the head of the screw creating backlash.
U.S. Pat. No. 5,957,628 discloses a milling cutter having a plurality of cutting insert retaining cartridges circumferentially spaced about the outer periphery of the cutter body. An adjustment mechanism for each cartridge includes an adjustment screw threaded into a corresponding bore in the cutter body. The axis of the adjustment screw is approximately parallel to the axis of the cutter body. The head of the screw engages into a groove in the cartridge to provide axial adjustment of the cartridge. In order for the head of the screw to engage the groove, the groove has to be dimensioned larger than the head of the screw giving rise to play or backlash.